Final answer:
Polysulfide rubber's working and setting times can be reduced by either raising the temperature or adding accelerators, which increase the speed of the sulfur vulcanization process.
Step-by-step explanation:
Polysulfide rubber (mercaptan) working and setting times can be shortened by increasing the temperature or by adding an accelerator to the mixture. Like most chemical reactions, increased temperature can increase the rate of the vulcanization process, thus shortening the time required for the rubber to set. In the context of sulfur vulcanization, accelerators such as zinc oxide and stearic acid may also be used to enhance the cross-linking efficiency, thereby reducing the working and setting times.